670 ARBORETUM AND FRUTICETUM. PART III. 
probably be their ultimate height, or whether they can be kept within bounds . 
by pruning, without injury or total prevention of flowering. This point re- 
quires consideration, or the plants are likely to become nuisances, 
Omphalobium, Virgilia, Sophora, several Psoralez and Cftisi, form a distinct 
stem: Schotia, Indigéfera, Psoralea, Aspalathus, Podalyria, Liparia, and 
Borbonia, as well as Cyclopia, Sarcophyllum, and Rafnia, form branching 
shrubs from the collar. In the three last-mentioned genera, this habit should 
be encouraged as much as possible, by cutting them down to the ground; 
which occasions the larger growth of the collar: and, in old plants, the ap- 
pearance of nakedness would be but temporary; while the quick growth of 
numerous shoots would soon form them into dense bushes, and stronger and 
more characteristic masses of flowers. Omphalobium and Schotia are of slow 
growth: planting them under the shade of others will draw them up to a re- 
quisite height without injury. 
Mr. Bowie gives the following list of the average height which several 
species attain in their native habitations, as a guide to the cultivator in 
planting : — 
Ft. In. Ft. In. 
Virgilia intrisa and capénsis 25 0 Indigéfera cytishides- - 8 O 
If Virgilia is deeply in- Podalyria styracifolia -' 9 0 
jured in the old wood, Aspalathus - 6in.to4 0 
a gum exudes, which is Rafnia (annual growth) 2ft.to 3 0 
used as gum Arabic. Sarcophyllum (annual growth) 1 6 
Omphalobium - - 12 O Liparia sphe’rica - — - 3 0 
Sophora sylvatica - - 16 0 Acacia capénsis, or nilética 20 0 
Psoralea pinnata = - - 15 0 Acacia cafras  - =o PS" 12" O 
Cyclopia - 4ft.to 10 0 
The latter thrives best by being cut down, and confined as a shrub to 6 ft. 
They both yield the gum Arabic. 
Erythrina cafra attains the height of 60ft., but flowers at the height of 
15ft. Erythrina nana, introduced by Mr. Bowie into England in 1823, 
flowers at 2 ft.; and may be considered as half-shrubby, as it scarcely ever 
attains a permanent stem: it is a desirable plant. 
A portable house, for the protection of half-hardy Leguminacez during win- 
ter, may be made in various forms, at very little expense. Two parallel walls, 
6 ft. or 8 ft. high, and 15 ft. or 20 ft. apart, in the direction of north and south, 
will leave a space between, which may be covered every autumn with tem- 
porary rafters, on which may be placed the sashes of hot-beds not in use, alter- 
nating with boards. If moisture has been withdrawn from the soil, by drain- 
age, and by covering with boards or with glass, or even by thatching the soil 
during heavy rains in autumn, so as to facilitate the ripening of the wood, 
there will be no difficulty in keeping the plants alive; and when they are cut 
in, in spring, they will push vigorously, and soon have a clothed appearance. 
CHAP. XLII. 
OF THE LIGNEOUS PLANTS BELONGING TO THE ORDER ROSA‘CEZR. 
Tue term Rosacez has been applied to this order, because all the species 
belonging to it agree more or less with the genus /dsa, in essential charac- 
ters. It includes many genera belonging to the Linnzan class Icosandria. 
Distinctive Characteristics. Flowers regular. Calyx, in most cases, with 
5 lobes, the odd one posterior to the axis of inflorescence. Petals and 
stamens arising from the calyx. Stamens, for the most part, numerous. 
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